In a meeting with New York Times reporters and executives on Tuesday, President-elect Donald Trump delivered a stunning about-face on his long-time support for torturing terrorism suspects, and despite months of bragging that he would bring back waterboarding and “a hell of a lot worse,” he now says it might not be an effective tool.

The change seems to have come after a meeting with retired Marine Corps general James Mattis on Sunday, who Trump said he is “seriously considering” to head the Department of Defense.

The president-elect admitted that when he asked Mattis about waterboarding, he was surprised that the retired general rejected the idea.

Mattis replied that he had never found abuse to be useful when dealing with detainees, Trump recounted to the newspaper. Instead, he advocated building a rapport with prisoners, something many in the intelligence community have been arguing for years is a more effective method of soliciting information. “Give me a pack of cigarettes and a couple of beers and I’ll do better,” Trump said Mattis told him. “I was very impressed by that answer,” Trump said.

Torture, Trump concluded, is “not going to make the kind of a difference that a lot of people are thinking.”

The admission raises questions over the incoming president’s understanding of the military’s view of waterboarding and torture, and if support for waterboarding had emerged as a litmus test for who the president-elect will nominate to be in his cabinet. All of Trump’s cabinet picks so far — for national security advisor, CIA director, and vice president — have called for abusive interrogation techniques to be re-introduced to the U.S. government’s counterterrorism toolbox.

Trump has long extolled the need for waterboarding terrorist suspects while on the campaign trail and in presidential debates, saying earlier this year, “I would absolutely authorize something beyond waterboarding and believe me, it will be effective.” During a Republican primary debate in February, he added, “I would bring back waterboarding and I would bring back a hell of a lot worse than waterboarding.”

In some ways, Mattis has literally written the book on rejecting torture and abuse as a tool for gaining information and waging war. In September 2005, the then-three star general published a 34-page document while serving as the Marine Corps’ Deputy Commandant for Combat Development and Integration, called “War Crimes.”

Mattis wrote that “Marines do not torture or kill enemy prisoners of war or detainees.”

He followed that up in his introduction by stating, “America is trusted by the world to do the right thing, and so must be the United States Marines. Following the rules, including the rules in warfare, must be a part of our warrior ethos. The application of honor, courage, and commitment in the conduct of military operations means: the honor to comply with the Laws of War, the courage to report all violations, and the commitment to discipline the violators.”

As the commander of the First Marine Division in southern Iraq in early 2003, Mattis wrote a letter to his Marines to “engage your brain before you engage your weapon,” and “our fight is not with the Iraqi people, nor is it with members of the Iraqi army who choose to surrender.”

Trump’s pick to be National Security Advisor, retired U.S. Army general Mike Flynn, has in recent months refused to rule out bringing back the use of waterboarding and other forms of torture for prisoners in American custody, despite a history of denouncing the tactics.

In December 2014, Flynn said torturing prisoners “exposes the United States to something that we — I think history will look back on it and it won’t be a pretty picture.”

Since joining the Trump campaign, however, his view has shifted. “I am a believer in leaving as many options on the table right up until the last possible minute,” he told Al Jazeera in May.

He even left the door open to killing family members of suspected terrorists, as Trump has suggested. Flynn said he “would have to see what the circumstances of that situation were” before making a decision.

In an interview with Politico just last month however, Flynn continued to express some misgivings.

“I would not want to return to ‘enhanced techniques,’” he said. “Having said that, if the nation was in grave danger from a terrorist attack involving weapons of mass destruction, and we had certain individuals in our custody with information that might avoid it, then I would probably OK enhanced interrogation techniques within certain limits.”

Trump’s pick to be the next director of the CIA, Rep. Mike Pompeo (R-Kan.) has also defended the use of waterboarding.

If the Trump administration did want to bring back waterboarding, it wouldn’t be easy, and would face stiff resistance from the Pentagon and some lawmakers. The chairman of the Joint Chiefs of Staff, Gen. Joseph Dunford, testifying before a Senate panel earlier this year, flatly rejected bringing back so-called “enhanced interrogation techniques.”

Congress has also rejected torture. In June 2015, the Senate voted 78-21 to adopt an amendment reaffirming the ban on prisoner abuse, while mandating that interrogation techniques should be guided by the Army and Marine Corps field manual, which does not include waterboarding.